Many current data demodulators implement the demodulation function, associated with a specific modulation scheme such as Motorola Radio Data Link Access Procedure (RDLAP) or Motorola Mobile Data Communications protocol (MDC), using a general purpose processor, such as a digital signal processor (DSP), executing a software controlled demodulation algorithm. Such processors, in particular DSPs are very flexible in that different data demodulators may be readily accomplished by changing a software algorithm. However, DSPs are relatively power-hungry and therefore may not be suitable or optimum for use in or as data demodulators intended for portable products where battery life is a concern. Such demodulators ordinarily seek to minimize power consumption and thus prolong battery life. Additionally the cost and physical space typically required for the DSP and associated memory for software is often contradictory to the objectives of a data demodulator for portable applications.
There are existing land-line data modem integrated circuits that effect a demodulation algorithm for a land-line or hardwired data modulation protocol. There are also modem integrated circuits which implement demodulation algorithms, such as RDLAP or MDC, for wireless data modulation protocols. Such modem integrated circuits can be arranged and constructed to have power consumption characteristics and physical space requirements that are advantageous for a portable product requiring demodulation capability for a sole data modulation protocol. However as alluded to above this approach has the disadvantages of being relatively inflexible if a different data modulation algorithm is desired. Furthermore, this approach is not feasible, or at least not practical, for addressing the wireless data market's needs to the extent that capability to effect multiple data modulation protocols is required.
Clearly an urgent need exists for a data demodulation logic unit that is adaptable to multiple data modulation protocols and satisfies the power consumption and space requirements of a portable product.